It is often desirable to place a sheet of material such as corrugated board under a load to protect the load against damage from lifting, transport or other handling operations.
Loads may either be too heavy to lift for placement of a bottom sheet, or it may be undesirable to interrupt progress of loads being transported for placement of bottom sheets.
Further, some loads such as stacked materials may become disheveled if lifted or otherwise shifted to allow access for placement of a bottom sheet. The stacked material in the load may shift or topple if lifted from an end or a side. Further, full access to the area under the load may not be permitted unless the entire load is lifted to provide clearance for placement of the bottom sheet or sheets.
Of course, loads may be formed on bottom sheets that are set in position before the load is formed. However, the sheets are often not of substantial weight and can easily shift position before the load is received. Further, the bottom sheet may interfere or disrupt a load accumulation process, especially in situations where the load is progressively formed in a stack.